Loud knock coming from engine - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 3 (permalink) Old 06-29-2006, 12:38 PM Thread Starter
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Loud knock coming from engine

I have recently noticed a loud and getting louder knock coming from my engine. I am bringing it into Kawasaki for evaluation this evening. To me it sounds like the pistons are smacking into something. I know it would only be speculation, but does anyone have any idea what this could be and what it might cost to fix? Meaning, am I looking at $300 to $500 or $1000 and up? I had my oil changed a few hundred miles ago and I think that is when I first noticed the knock. It is much louder now.

Also, I have changed the ACCT before and I am familiar with this sound. I do not think it is the ACCT. In fact I was changing the ACCT spring and heard the chatter as well, until I correctly installed the plunger.

Any info would be appreciated.



Last edited by Vaccam; 06-29-2006 at 12:46 PM.
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post #2 of 3 (permalink) Old 06-29-2006, 01:20 PM
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I have the same problem, have a thread going as well. If you do take it in and find out what it is, please post it, so I know what I'm gettting into too. I spent $200.00 for the bike, and a few months of aggrivation to get to this point... and the wife still gets upset if I spend 50 cents on an O ring. ( did I mention she hates bikes?...... Oh yeah, I guess I do mention it in every posting)

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post #3 of 3 (permalink) Old 06-29-2006, 03:55 PM
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Take the one of the plugs outta each cylinder, and see if you can see anything, like damage. Might take the left side cover off and turn the engine manually (CCW, I think), and see if you can see the valves. It would help if you had a boroscope! If it's a valve hitting the cylinder, you should be able to see an impact point on the piston, and maybe a damaged valve. But if the bike appears to be running OK other than the noise, it may be deep in the bowels of the crankcase.

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